Origen

The Latin word costa meant ‘rib or side’, which is why coast meant ‘rib’ and ‘the side of the body’ from Anglo-Saxon days right up until the start of the 19th century. The sense is still found in French côte de porc (where the ^ stands for a lost ‘s’) for ‘pork chop’ referring to the rib bone, and in the word cutlet (early 18th century) ‘a little côte’. The phrase coast of the sea—meaning ‘side of the sea’—gave rise to the modern use, ‘the part of the land adjoining the sea’. The verb originally meant ‘to move along the edge of something’ and ‘to sail along the coast’. The coast is clear originally signalled that there were no enemies or coastguards guarding a sea coast who would prevent an attempt to land or embark by sailors or smugglers.